He said a more specific description was not available because authorities had not determined what specific kind of device was used.

The incident occurred around 2:30 p.m., with witnesses reporting a "boom" and seeing white smoke rising from a trash can on the sidewalk on North Calvert Street in front of the courthouse. After closing surrounding streets, officials guided a robot to the trash can to pick through its contents.

No one was injured, and damage was limited to the inside of the trash can.

Cogen said footage from surveillance cameras was being analyzed to determine whether they could develop a suspect.

"This crime is being taken very seriously, and your best course of action is to immediately turn yourselves in to law enforcement authorities," Sheriff John W. Anderson said in a statement that officials said was directed to the person who set off the firecracker.

Salisbury University has suspended its Phi Beta Sigma fraternity chapter for hazing, after members were reported to have hit pledges with paddles and held forced workouts at an off-campus house, school officials said.